Mulch Suppresses Psyllids in Young Trees 

Tacy Callies Psyllids, Tip of the Week


By Jawwad A. Qureshi, Lauren Diepenbrock and Davie Kadyampakeni 

Protecting citrus trees from the Asian citrus psyllid (ACP) is critical to reducing the spread and severity of huanglongbing (HLB) disease. The frequent availability of viable shoots in young trees is attractive to psyllid colonization, feeding and oviposition events. UV-metalized reflective mulches reflect ultraviolet light, which is disturbing for some insects such as ACP, a day-flying insect that primarily relies on vision to locate its host.

University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers are determining the effects of 96-inch-wide UV metalized Shine N’ Ripe XL reflective mulch on ACP in newly planted citrus. The plantings include Ruby Red grapefruit in Vero Beach and Valencia sweet orange in Immokalee and Lake Alfred.

The effects of mulch on ACP suppression during the initial two years of planting resulted in reduced adult numbers in Immokalee and Lake Alfred by 60% in 2020 and 44% in 2021. The effect of mulch on shoot infestation with psyllid immatures was observed up to 65% at Vero Beach. However, researchers did not see as large of a difference in the number of nymphs in each treatment in Lake Alfred. With the increase in the canopy size, trees with mulch had reduced psyllids and only 8% more shoot infestation in mulch than bare ground at Vero Beach and Immokalee in 2022.

The number of fruits collected per grapefruit tree on mulch was almost double than that collected from a tree on the bare ground, averaging 11 and 6 per tree, respectively. Fruit weight was 65% higher on the mulch. In Valencia oranges, benefits in yield are not apparent yet. The trees on mulch are in better health with larger trunk diameters and canopies. 


  • ACP suppression was significant for two years on trees with mulch. 
  • Trees on mulch were healthier than those on the bare ground.  
  • The benefits of mulch are expected to increase on larger plantings with greater protection against ACP and benefits of moisture and nutrient conservation, which may vary with soil type. 

Acknowledgment: The Citrus Research and Development Foundation funded this project.

Jawwad A. Qureshi is an associate professor at the UF/IFAS Southwest Florida Research and Education Center in Immokalee. Lauren Diepenbrock and Davie Kadyampakeni are assistant professors at the UF/IFAS Citrus Research and Education Center in Lake Alfred.